I noticed Walmart now sells Rotella oil in a synthetic blend - both in 10W30 and 15W40. It is in a silver container and has the CI-4 designation on the back. I assume it still has the zinc additive needed for our valve tappet lubrication. I have been using the Rotella full synthetic 5W40 in the blue container for my turbo 180. Price difference is roughly about $10. All comments are welcome.

Synthetic blends can be done for different reasons. Sometimes because your base oil is too weak to pass standards, so you blend in some synthetic. Sometimes for marketing: In this case you can put in 1 or 2% and call it that. And sometimes you have a specific standard you need to meet for a specific manufacturer, so you use it.

Nothing wrong with it, treat it as a slightly bette than mineral. ZDDP will still be the same as other CI-4 oils.